Each entry was broken down by the MP’s first and last name, the job he or she performed, who paid them, how long the job took, how much they were paid, when a payment was formally registered, and the party to which he or she belongs.

Information on when the work in question was actually performed was also included where available.

Some MPs declined to say how many hours a job took, instead measuring their efforts in days. In the absence of evidence to the contrary a basic eight-hour working day had to be assumed.

A handful failed to include any such information - in which case a zero entry seemed more appropriate than a figure made up to approximate the length of time taken.

Some MPs chose to enter payment as gross, others as net. In each case only the figure given was used.

Some MPs gave travel time alongside the duration of a job or task. Others, including those making trips to far flung corners of the world, did not.

This left no option but to include only the number of hours entered in the Register, even though the true tally was likely to be far higher.

Detailed notes were also kept and any rogue entries from 2013 were excluded from the dataset, as were entries dated 2015.

Sponsorships (details of which are held separately by the Electoral Commission), income from land or property, overseas visits, gifts in kind, benefits and hospitality in the UK and abroad were not considered.

Shareholdings were also ignored, unless the MP revealed themselves to be a shareholder in a company – often one they own – from which they also received cash payments.

Many MPs chose to give income from completing opinion polls and surveys to charity, local or other non-profit organisations, or to constituency or national party political groups.